ebay api - search php call

[Kicks]

Im trying to perform a simple call using ebays search API, when I make a call I get no response, and the problem is with the actual call itself.\[code\]$endpoint = 'http://open.api.ebay.com/shopping?'; $responseEncoding = 'XML'; $version = '631'; // API version number$appID = 'asdf3e6e3'; $itemType = "AllItemTypes";$itemSort = "EndTime";//find items advanced$apicalla = "$endpoint" ."callname=FindItemsAdvanced" ."&version=$version" ."&siteid=0" ."&appid=$appID" ."&MaxEntries=10" ."&ItemSort=EndTime" ."&ItemType=AllItemTypes" ."&IncludeSelector=SearchDetails" ."&responseencoding=$responseEncoding"; $resp = simplexml_load_file($apicalla);\[/code\]this call is the equivalent to \[code\]http://open.api.ebay.com/shopping?callname=FindItemsAdvanced&version=631&siteid=0&appid=asdf3e6e3&MaxEntries=10&ItemSort=EndTime&ItemType=AllItemTypes&IncludeSelector=SearchDetails&responseencoding=XML\[/code\]My question is what am I missing to make this simple search call?